▎ 摘　　要

NOVELTY - Preparing ultra-thin silicon carbide nanosheets comprises adjusting concentration range of the surfactant polyvinylpyrrolidone to 0.02-0.5g/mL, using graphene, reduced graphene oxide or graphene oxide as template, and mixing chloroform and nitrogen dimethylformamide in a volume ratio of 0.5-3. The adjustment range of silicon carbide precursor concentration is 2-12 μL/mL. The preferred fully dissolved surfactant polyvinylpyrrolidone is fully mixed with the preferred template under stirring for 15-30 minutes, passed inert gas into for 5-10 minutes, then added the preferred polycarbosilane under stirring for 10-24 hours to obtain composite material combining polycarbosilane and template. The selected freeze-drying agents include tert.-butyl alcohol, deionized water, acid solutions with different pHs, dimethyl sulfoxide, preferably dimethyl sulfoxide. USE - Method for preparing ultra-thin silicon carbide nanosheets used in electronic devices, micro mechanics, engineering, and materials (claimed). ADVANTAGE - The method provides a high-quality silicon carbide nanosheet with adjustable thickness and controllable material phase. DETAILED DESCRIPTION - Preparing ultra-thin silicon carbide nanosheets comprises adjusting concentration range of the surfactant polyvinylpyrrolidone to 0.02-0.5g/mL, using graphene, reduced graphene oxide or graphene oxide as template, and mixing chloroform and nitrogen dimethylformamide in a volume ratio of 0.5-3. The adjustment range of silicon carbide precursor concentration is 2-12μL/mL. The preferred fully dissolved surfactant polyvinylpyrrolidone is fully mixed with the preferred template under stirring for 15-30 minutes, passed inert gas into for 5-10 minutes, then added the preferred polycarbosilane under stirring for 10-24 hours to obtain composite material combining polycarbosilane and template. The selected freeze-drying agents include tert.-butyl alcohol, deionized water, acid solutions with different pHs, dimethyl sulfoxide, preferably dimethyl sulfoxide. The obtained polycarbosilane is combined with the template to remove the reaction solvent, where the bottom solid is collected, and then washed twice with a mixed washing solvent to obtain a clean, dry, well-dispersed sheet-like polycarbosilane composite material combined with a template. The obtained composite material is placed into a tube furnace, and passed in an inert gas to carry out temperature programming at 800-1600℃ to obtain composite materials of amorphous, amorphous-crystalline, and crystalline silicon carbide nanosheets and templates. The obtained composite material is placed in a muffle furnace, and the templates are removed under an air atmosphere to obtain amorphous or amorphous-crystalline or crystalline silicon carbide nanosheets.